Proper maintenance of a vehicle's engine is an important priority in the daily operation of a vehicle. Without proper maintenance minor problems can escalate into major mechanical failures, resulting in costly downtime and expensive repairs.
Typically, when an operator observes a performance loss of power in a vehicle's engine, the vehicle is brought into the shop for testing and repair.
Unfortunately, the best time to diagnose power-related problems is during the typical driving conditions. In the shop, test data may be collected using a dynamometer. However, this data is really only useful for verifying that a power problem exists. It does not necessarily locate the problem.
Therefore, the best way to diagnose the engine is by collecting data during operation and analyzing the data. Generally, this type of analysis has been confined to collecting the data and comparing the data to standard or normal graphs. The problem with this type of method is that it does not provide on-board or real-time diagnostics. It also requires that an operator recognize a loss of power and that the vehicle is brought in for maintenance. Furthermore, it requires a great amount of skill and knowledge to equate deviations in the engine parameters to a type of problem or the location of the problem.
It is also known to use computer-based models for diagnosing an engine. Reference for instance, Brown, Jr. et al. U.S. Pat. No. 5,377,112 issued Dec. 27, 1994 and Rutan et al. U.S. Pat. No. 5,526,266 issued Jun. 11, 1996, both to Caterpillar Inc.
However, diagnosing a combustion related problem in an individual cylinder or bank of cylinders of an engine has been found to be difficult when using the known models.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.